Seeds Germination For Ecology Adaptation Puionium Gaertn. Plants

Pugionium Gaerten. is a very important shrub species for sandy vegetable inhabilitation in Inner Mongolia of Inner Mongolia Autonomous Region China for its high ecological and economic values. P. cornutum (L.) Gaertn. and P. dolabratum Maxim. is its two species. They grew up in mobile and semi-mobile dunes. Usually in this habitat, there is a high temperature, drought, temperature difference between day and night and salt accumulation. Controlled experiments were conducted to investigate on seed germination of P. cornutum and its congeners P. dolabratum, for this experiment, the temperature, different sand burial depth and indoor storage means and osmotic NaCl and isotonic PEG, to better understanding how they adapt to desert habitats at seed germination stage. The results indicate:1. At constant incubating temperature and darkness, Storage for 1 and 2 years seed of P. cornutum and P. dolabratum can germinate at gradients from 15 to 35°C, and the germination percentages of P. cornutum were significantly higher than those of P. dolabratum at 15°C and 35°C respectively. The optimal germination temperature for P. cornutum and P. dolabratum were 25°C and 30°C respectively. Under alternating temperature and darkness conditions, the optimal temperature for seed germination of two congeners was both occurring at 20/30°C. Percentages of seed germination were higher at 20/30°C than their respective optimal constant temperatures of both species; In addition, seedling hypocotyl and radicel length of both species developed at 20/30°C were shorter than that at 25°C and 30°C respectively, but their dry weight were not obviously declined. Indicating alternating temperature has advantages for seed germination and seedling development of two congeners. In these temperature treatments, P. cornutum and P. dolabratum seeds were stored for 2 years than 1 year of seed storage.In summary, darkness and 20/30°C daily alternating temperatures are the favorable conditions for seed germination and seedling establishment of these two desert species.2. The original wild habitats, 0 cm, 1 cm, 2 cm and 5 cm buried for 6 months and 5°C room temperature storage for 15 months at room temperature storage of P. cornutum seeds and seed vigor quite 2 years; All indoor storage of seed processing, seed longevity this species were more than 2 years; Wild seeds buried 50 cm of treatments, P. cornutum seed was also the longest seed bank longevity expectancy more than 2 years, followed by the 0 cm burial treatment seed bank longevity were 15 months, in 1~10 cm burial treatment P. cornutum seed bank longevity span of only 6 months.3. P. dolabratum seeds had stronger salt tolerance than P. cornutum; Seeds had the strongest salt tolerance at 20/30°C, seeds could furthest tolerate 300 mmol·L-1 of NaCl solution. Salt tolerance in descending order of P. cornutum and P. dolabratum seeds was: 20/30°C >25/35°C >15/25°C >10/20°C. Seed of P. cornutum and P. dolabratum were the germination and germination rate reached the maximum by 200 mmol·L-1NaCl pre-treatment at 15/25°C, 20/30°C and 25/35°C; Seed recovery of germination rate was more than 90%, and germination rate of recovery was more than 80. In summary, NaCl pre-treatment seed germination of recovery was rapid and orderly in the temperature.4. The ability of resistance to osmotic stress of P. dolabratum seeds was stronger than that of P. cornutum seeds; the ability of P. cornutum and P. dolabratum seed germination were strongest at 20/30°C, Seeds were patient of -1.0 MPa PEG furthest; the descending order of capacity of osmotic adjustment in the temperature-resistant of P. cornutum and P. dolabratum seeds was: 20/30°C >15/25°C >25/35°C >10/20°C. Seed of P. cornutum and P. dolabratum were the germination and germination rate reached the maximum by -1.0 MPa PEG pre-treatment at 15/25°C, 20/30°C and 25/35°C; Seed recovery of germination rate was more than 90%, and germination rate of recovery was more than 80. In summary, PEG pre-treatment seed germination of recovery was rapid and orderly in the temperature.5. Antioxidant enzyme activity of P. dolabratum seeds was higher than P. cornutum seeds; NaCl pre-treatment had increased Pugionium Gaerten. plant seeds antioxidant enzyme system capacity; The resulting effect of ionic effects and osmotic adjustment increased APX , SOD and POD enzyme activity in seeds. Simply osmotic adjustment generated by the PEG had been improved POD enzyme activity and reduced the lipid peroxidation in seeds.